Asda shoppers have been taking advantage of a computer glitch on the
supermarket’s website that has allowed them to claim food vouchers worth
thousands of pounds.

The supermarket’s Price Guarantee pledge gives shoppers money-off vouchers if they paid more for their weekly shop at Asda than at any of its large rivals. Under the scheme, Asda will also add 10 per cent to the value of the vouchers.

Shoppers take part in the scheme by typing details from their receipt into Asda's website.

However an error in the computer system has been undervaluing some rivals’ products, meaning that Asda has had to pay out more vouchers than it should have.

Internet forums have been full of tips about how people can make money from the error. Some customers have been making up to £40 per shop from the glitch.

However one shopper claims to have made over £8,500 from Asda in recent weeks.

In an attempt to put an end to people taking advantage, Asda has put a cap of £15 on the amount of vouchers that it hands out per shop.

Supermarkets are involved in a bitter price war as household budgets come under continued pressure from the rising cost of living and slow wage growth.

An Asda spokesman said there was a “small” glitch on its website has meant that a “very small number of our savviest customers have been able to beat the system and claim a few, larger than normal, money-off vouchers”.

The spokesman confirmed that from Sunday it had capped the value of the vouchers it gives out from one transaction at £15.

“Customers can still claim up to £100 in APG vouchers per calendar month, or up to ten vouchers in a month but not exceeding £100. This is monitored through the website, and colleagues will not be required to enforce this in store,” the spokesman said.

The supermarket, which is owned by Wal-Mart, the world’s largest retailer, said that over 99 per cent of vouchers are issued for less than £15. It said that the cap will have “no impact whatsoever on the vast majority of customers”.

“We will continue to offer the most transparent, robust price comparison in the market and maintain our guarantee to be 10 per cent cheaper than our rivals on a comparable basket of groceries, or we will refund the difference,” the company said.